Efforts to improve flow and heat transfer rate in small sizes has been shown in IEEE EDL-2, pages 126-129, wherein microgrooves and microwhiskers are placed on the back of integrated circuit chips. The use of the latent heat of evaporation of a liquid has been recognized as an efficient cooling means in U.S. Pat. No. 4,322,737 wherein a fluid is evaporated in microgrooves and in the technique of transpirational cooling described in Chapter 12-3, pages 509-513 of a book on Heat Transfer by J. P. Holman, published by McGraw Hill, wherein a fluid is forced through a sintered plate into the boundary layer of a gas stream.